Process for the production and use of novel tanning agents and products produced by such process



PROCESS FOR THE PRODUCTION AND USE or NOVEL TANNING AGENTS AND PRODUCTS PRODUCED BY SUCH PROCESS Lucien Sellet, Saddle River, NJ., assignor to Jacques Wolf & 00., a corporation of New Jersey N Drawing. Filed Sept. 23, 1952, Ser. No. 311,149

26 Claims. (Cl. 260-676) weight organic compounds containing at least one sulfo' gr'oup, and novel products produced by said method,lsaid method and products being of particular importance 'in.

the leather industry. 1

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the. invention,

the "same being realized and attained by mea'nsof the steps and compositions pointed outin' the appended claims.

' The invention consistsin the novelsteps and composi-;

tions herein shown and described;

An object of my invention is 'to formaldehyde'resin having at least onereactive hydroxy group with an amino compound having at least one'func-T tional amino group whereby a condensation reaction takes place by the reaction of the hydroxy and amino groups.

' Another object of my invention is to provide a novelmethod for treating materials, penetratable or:porous in nature, and in particular leather compositions, corn prising dispersing a modified amino-formaldehyde resin and a high molecular weightsulfo compound on said objectbeing treated andproviding an acidic environment whereby'said sulfo compound and amino-formaldehyde resin react so as to form a water insoluble addition com-' pound which remains fixed to the object being treated.

A still further object of my invention is to provide novel coated materials formed in accordance with the process described in the above paragraph.

"The' term amino-formaldehyde resins as used throughout the present-specification, vrefers to thewell, known water soluble or water dispersable resins formed by the condensation of an amino compound having functional amino groups with suitable amounts of an aldehyde, preferably formaldehyde, with or without a catalyst, at temperatures generally above room temperature. Also, the term amino-formaldehyde resin as used hereinafter is meant to include a resin produced in accordance with V produce modified; amino-formaldehyde resin, which isstablein water and possess'escation active properties, by reacting an amino United States Patent 0 resins as tanning agents. 'In many cases, these resins: produce undesirable side eifects which are difiicult to control and often can not be controlled at all. It is well. known, for instance, that some of these resins during application to leather are lacking the right penetration In other-i, cases, the tensile. strength of the treated leather is some-f.

and cause crackiness of the treated leather.

times considerably lowered.

In order to produce water soluble or water dispersable resins which have all the desirable properties of the well known aminoformaldehyde resins but which are far more stable when in an' aqueous medium, I have invented at novel process whichI consider to be quite important in,

the resin field.

My novelprocess in general consists in reacting an aminoplast resin having at least one reactive hydroxy'l group with an amino compound having at leastone func-.,'

tional amino group to form a condensation product which.

- is stable in water solution and will not polymerize or the conventional process described above, and whose "seriously detract from the use of said amino-formaldehyde condense therein and which has cation active properties;

Moreparticularly, my iinvention relates to a process for modifying the amino-formaldehyde resins'which have;

been prepared by the condensation of at least one mole of formaldehyde with anamino compound of the type illustrated by urea, thiourea, guanidine, acetylene diurea,.

melamine and dicyandiamide. These amino-formalde-v hyde resins contain at least one reactive methylol groupv which limits'the stability of these resins since they tend to f polymerize or condense when in an aqueous mediunn By reacting one of the above referred to amino-formal-v groups in a mole of the amino-formaldehyde resin as well as the number of functional amino groups inthef amino compound. The proportions should be such that all of the reactive hydroxy groups in the amino-formaldehyde resin are eliminated by reaction with an equal. number of functional amino groups in the amino .com-- pound. Hence, the amount of a specific amino com-, pound which would be reacted with a particular aminoformaldehyde resin would well be within the skill of one in the field in view of the above description. I

The reaction is preferably carried out at temperatures between the range of C. to C. Also, the time of the reaction will vary in different cases, the tirne being usually in the range of about 3 to about 10 hours. As is well known, the time may be decreased by increasing the temperature and vice =versa. The pH of the reaction medium is preferably slightly acid, neutral or slightly alkaline in nature. Preferably, an alkaline catalyst such as borax is used to speed up the reaction. Advantageously, the modified amino-formaldehyde resins produced in accordance with my process are Water soluble orwater dispersible and maintain their stability in Water. They have very good penetrating properties. which make them very useful as fillers in'treating 'materials, penetratable or porous, in nature, such as leather,

paper, fabrics, etc. A Water solution or dispersion of said resin is applied to said porous .or penetratable material. wherebysaid resin adheres to said material and fills the pores thus' producing a smooth finish to said material.

One of the outstanding uses of my novel cation active modified amino-formaldehyde resins is theiruse in con 1; bination with an anion active water soluble or water dis- Patented July. 5, 1960.

jpe'rsible molecular weight organic compound cont aining one or more sulio groups, the sulfo compound either being in the form of a neutral salt or in the form t a mpoumi havingat e ie r u t e the r -w nijentjoiileatherf compositions... A r. p V j'According to the .last mentioned aspecto'f my invention,

3 the .n jodified amino-formaldehyde. resin and, sulfo compoundf'aredi'spersed on theleather by means of an aqueousgbathwhereby they'react; under acidic conditions to form'fajwater'insoluble compound which improves the a; 4 a Omega sulfonate of dihydroxy dimethyl diphenyl sulfone, omega'sulfonate of dihydroxy diphenylsulfone, omegatensile" strength, flexibility, resistance to. cracking and V resistance to abrasion of the tre'atedlleather.

fHQI-IPB; if the suite compound is inthe form of a neutral salt, the sulfo compound and modified amino-formalyderesin a e P i n queous b h n e leather 7 isj treated with said bath for a sufficientperiod of time,

usually three or four, hours, until the sulfo compound nd mod ied .amin c ld y ees n h bedtime tqbe absorbed byjhe leather. Of course, either the 'niodified, amino formaldehyde; resin or sulr'o compound nii'ay lbe'dispersedon the leather alternatively instead of im l eous y; so d s d, but ti adva t to tr'ejat'jthe leather simultaneously for the time oftreatment 7 sisho tene i W en b etael a f t O 't H compound and the modified aminoformaldehyde resin: liave been absorbed by the leather, anacidic compound- .such assulfurijc acid, citric acid; lactic 'acid,idiglycolic operable such 'as the s'odium, potassium and ammonmm salts 'as illustratedfby' the sodium salt of disulfo dinaph;

thyl methane, the sodiu'm salt ofdisulfo, dihy roxydi acid, etc;. orjan acidic salt such ias aluminum sulfate,

tof 'bring the pH ofthebathto adeiinite acidic environ njengior example apH pi -about 3 or 4, whereupon'the s'u'lfo'j compound andrnodified amino tormaldehyde resin. reactiorming a water insolublecompound which're'mains ZWhen a sulfo compoundis used which has a free s'ulfo rourseasltd .h ac d in nat reth sulfo c p 'a'ndmodifiedaminoaformaldehyderesincan not be added tojthe' bath simultaneouslysince due to the'acidic nature 1 f of; the sulfdeomppundareaction would take place immedia'tely, wherebya water insoluble compound would be 'for niedfinthebath, and a sujficient amount of said comchloride, sodium bisulfate isadded to the bath} Idehyde resins in accordance with my present invention; 3 35.

p'oundfwouldlnot be absorbed'by the leather. .Hence,

when a sulfo compound'havingthe sulfo group in the free state is used, the leather must be treated with either thefsulfo compound or modified amino-formaldehyde resin i irst,. and subsequently with the other, but not 7 simultaneously.

1 illustrative examples of sulfo-compounds which may be used arelignin. sulfonate and. its neutral salts such as sodiumsulfo lignin and magnesium sulfo lignin; vegetable such as wattle extract solubilized by sodium bisulfite' aswell as quebracho extractsolubilized by sodium bisulfite and the neutral water soluble salts of these extracts produced by neutralizing each of these extracts with a base such as sodium hydroxide, ammonium by droxide and p'otassium hydroxide; synthetic tannins known of thephenoLcresol etc. compounds containa sulfo group. Illustrative examples 'of these compoundsare:

disulfo dinaphthol methane, disulfo dinaphthyl methane,

monosnlfo dihydroxy diphenyl methane, a complex reaction product, formed by reacting monosulfordihydroxy methane with formaldehyde, to give the formula;

,M A A sulfonate of dihydroxy diphenyl propane, disulfo dihy: droxy diphenyl propane, disulfo dihydroxy diphenyl sulf0ne, and complex compounds containing a. benzidine radical with a sulfonimidlb idge as illustrated by the following compound:

The 'water soluble salts qof these compounds 9.15:0

phenyl propane 'andthe sodiums alt ofdisulfodihydroxy diphenyl s'ulfone.

- 'In'order to illustrate the inventionbyworlring examples. a the 'followingexaniplesl are now'gilvent Examples :1-16! are directed to the preparation-of modified amino-fo m l:

If so desired thefnfiodified-aminoformaldehydel I i may be prepared in the prescncelof an anionicqactive:

sulfo compound which is neutraIas'iIIuStratedbY. Ex; amples 17-22. advantageous forjthe modified amino-formaldehyde resin which is formed and the suite; compound are already combined and may immediatel 1 betdi'spersed in. an aqueous bath for treatment of leather ina manner hereinafter described in detail. Examples; 1

23 to 34 aredire'cted to the manner of treatingleather with the modified 'amino formaldehyde resins and high molwllar. weight sulfo p unds in accordance with the present invention. T e

' Example I guanidine carbonate andi243 grms, formal dehyde 37 %'i are mixed together in a flask equipped with; reflux and refluxed at a temperature of C.'for 1 hour. 168-grms. dicyandiamide are then added and the mixture isrefluxed 'at .809; C. for V6 hours, the pH o f. the final reaction product being about 1015 7 Example II i 180 guanidine carbonate and 243 grms. formaldehyde37 areheate'd together ina flask equipped with reflux, the temperature being brought to 80-90 for; V

onehour. 12 6;grms. of melamine are added and the mixture is heated and refluxed 4 hours at C., the' pH-of the final reaction product being about 10.3.

' e Example III;

guan idine carbonate @1243 grmsx formal- 7 dehyde 371% areheated together in a flask equipped with reflux, at a temperature from 80 to 90' C; for 1 hour;

228 grins. thiourea are then added and the mixtureis heat r a d refluxed for" 4 hours at 903 'c., the n r v v 7 guani inecarbonateanf243 sthma; deh'y .37,%1a eh at c1 e h aifiask e pp d. fl

mixture is heated and refluxed for 4 hours at 90 C.,

the pH of the final reaction product being about 9.9. Example V at 95 C., the pH of the final reaction product being about 9.5.

Example VI 60 grms. urea and 162 grms. formaldehyde 37% are heated together in a flask equipped with a reflux condenser. The temperature is brought to 80 C. for 1 /2 hours. 360 grms. guanidine carbonate and 200 cc. water are then added and the mixture is heated and refluxed for 5 hrs. at 80 C., the pH of the final reaction product being about 10.2.

Example VII 120 grms. urea, 648 grms. formaldehyde 37% and 3.8 grms. borax are heated together in flask equipped with a condenser, at a temperature of 80 C. for 1 /2 hours. 84 grms. dicya'ndiamide are then added and the mixture is heated and refluxed for three hours at 80 C.

To this product which has no cation active properties are added 84 grms. dicyandiamide and the heating is continued for '4 hours at 95 C., the pH of the final reaction product being 9.0.

Example VIII 7 '142 grms. acetylene'di-urea, 324 grms. formaldehyde 37% and 1.4 grms. borax are heated together in a flask equipped with reflux, the temperature being brought to 95 C. for 4 hours. 180 grms. guanidine carbonate are added and heated and refluxed for Z'hours at 95 C., the pH of the final reaction product being 10.3.

Example IX Example X "284 grms. acetylene di-ur'ea, 652 grms. formaldehyde 37% and 1.25 grmsl' borax are mixed in a flask and refluxed for 4 hours at 85 C. under stirring.

470 grms. of the final product formed above are mixed with 168 grms. dicyandiamide, This mixture is heated and refluxed for 11 hoursin arflask equipped with a reflux. Keepingtemperature at 95 C., the pH of the final reaction product being 8.1.

v Example XI 1 incl '84 grms. dicyandiamide, 4 mol 324 grms.

formaldehyde 37% and 1.2 grms. borax are mixed in a flask and heated and refluxed for 4 hrs. at 95 C. t 142 grms. di-acetylene urea powder are added and the the mentioned test shows a cloudy 'solutiomattliat time mixture is heated and refluxed for 10 hrs. at C., the 7 pH of the final reaction product being about 8.5.

I Example XII I 1 168 grms. dicyandiamide, 648 grms. of formaldehyde 37% and 3.6 grms. of borax are mixed and heated and refluxed at 95 C. for 3 /z hours. V V V p 336 grmsrof-dicyandiamide are added and the mixture Example x111 84 grms. of'dicyandiamide are mixed with 324 of formaldehyde 37% and 1.6 grms. of borax. The mixture is heated together in a flask equipped with reflux, at a temperature of 95 C. for 4 hours.

The mixture is cooled and 180 grms. of guanidinecarbonate and 208 grms. water are added and the resulting mixture is heated and refluxed for} hrs. -at 95 C., the pH of the final reaction product being about 10.0.

Example XIV 84 grms. of dicyandiamide, 324 grms. of formaldehyde 37% and 1.2 grms. of 'borax are mixed and heated togetherin-aflask equipped with reflux. 4

The temperature is brought .to 95 'C. 'for 3 his, the pH at the end of the react-ion being 8.5.

240 grms. of urea are added and heated and"'rfluxed at 95 C. for 5 hrs, the pH of the final reaction product being 9.9.

Example XV 84 grms. of dicyandiamide, 162grms. of formaldehyde 37% and 1.2 grms. of 'borax are mixed and heated to gether'in aflask'equipped with reflux.

The temperature is brought to 95 C., the reaction being controlled by introducing 1 cc. of the reaction liquid into a cc. cold water. -At'the beginning of the reaction the mentionedtest shows 'arperfectly clear solution. As the reaction progresses, and after 25 to 30 minutes the mentioned test shows a cloudy solution, at that time grms. of urea are introduced and heating is con- 'tinued for 2 hours at 95 C.

Subsequently, 324 grms. of CH O 37% Tare added and the reaction is completed by heating further for 4 hours at 95 C., and the pH of the final reaction .product being Example XVI 84 grms. of dicyandiamide and 162 grms. of formaldehyde 37% are heated together in a flask equipped with reflux.

The temperature is brought to 95 -C., the reaction being controlled'by introducing 1 cc. of the reaction liquid into a 100 cc. cold water. At the beginning of thereaction the mentioned test shows a perfectly clearcsolution. As the reaction progresses, and after 25 'to'30 minutes 120 :g'rms. of urea are introduced and heating is'Tcontinued for 2 hours at 95 C.

Subsequently 162 grms. of formaldehyde 37% are added and the reaction is completed by heating further for 4 hours at 95 C.,thelpH of the final reaction product being 8.9. V r

Example XVII 180 grms. of guanidine carbonate, 243"grms. of :torma'ldehyde 37%, 1580 grms. of the sodiumsalt of disulfo 'dinaphthyl methane in 35% water solutioniareheated and refluxed at 80 C. for lhour. 168 of dicyandiamide is then added and the temperature'is raised to 95 C. and refluxed for 6 hours. TheipH of the 'final mixture is 10.'5.- T

7 Example XVIII 1580 grms. of the sodium salt of disulfo dinaphthyl methane in 35% water solution are heate'd'under reflux at 95 C. with 324 grms. of formaldehyde 37% and. 84 grms. of dicyandiamide for '4 hours. 1'42 o'fQdiacetylene urea are then addedand the mixture is then heated at 95 C. for 8 hours, the pH of the final mixture 'pH of the final reaction product being 9.7.

being 8.5. V

v Example XIX 90 grms. .u'rea, 243 grms.jformaldhyde.37.% .and 15 grms. borax are heated together."i n} flask equipped withra hours. 63 'grmsmelamine "and 500 of the sodi uin "84 grms. dicyandiamide are then added and theresulting a n una'p saC:

salt of disulfo dinaphthyl methanein 35% water. solution are added ,to the aboveproduct; jlhe product isthen jheated' and refluxedrfor 4rhou'rs at 805C. 1 V .1 1; ExamplaXX V 63 grms. melamine,'243 grms. formaldehyde 37%, and 790'grms. sodium salt of disulio dinaphthyl methane in y'--35%;wate r solution are mixed. and heated'itogether, in

The'temperature is brought to 80" C. for 1 hour and '180 grins. urea are thenladded and the mixture is heated and refluxed at 80? (2. for .4 hours. a i

"Ihetemp'erature is then brought to 95 C. for 4 hours.

'mixture is heated and refluxed for 9 hrs. at 95 C.

1 f I? "E V I QV X 5, i V 1 e. s4 dieyandiamide, 324 formaldehyde 31% and 1.8'grms. borax are mixed and heatedtogether in a flask equipped with reflux.

' The temperatureis brought to9S C; for .4 hours. l42fgrms diacetylene u'rea'are then added andathe resulting mixture is heated and refluxed for 1 hour at 95 C.

Ta this mixtui'e is added 1,000 grms. sodium salt of di-' -sulfo dihydroxy diphenyl sulfone in 50% water solution and e the resulting isheated and refluxedior 1-0 7 cyandiamide formaldehyde resin modified by dicyandi amide and the sodium salt of d-isulfo dihydroxy diphenyl propane solution Seven gallons of water are added along withjthe a bove mixtnre.,- The skins are then treated -with thexbath for 1-hour. 1 pound of sulfuric acid 66 :-.B. is then addedlbringinge the pH of the bath to about 3. '"zThe skins are left in theacid bath for A bour during -which perioda water insoluble compound is precipitated on the skins. The are thenlwashed for /2? hour and areifat liquored with4 pounds of sulphonated sperm V 8 V V V V cyandiamide and the sodium salt; of -disulo-dinaphthyl methane. The skins are then treated with the bath for 1 hour, after which, /2 pound of sulfuric acid 66 B. is

tated on'the skins. The skins are then washed for V2 7 sperm oil; I l

1 "Example XXVI 7 V a :i 100 pounds of calf skins, chromeemailedall1 shaved are put into a drum containing a washing solution and are washed iz'or fit hour. The drum is drained and 3 pounds of a modified amino-formaldehyde resinrprepared' .in accordance with Example lI'are added along;with

gallons of water, said resin being a guanidineformaldehyderesin modified by dicyandiamide; The skinsar'e vthen treated withrthe 'resinbath for 1 hour, after whichl7 pounds of disulfoldinaphthyl methane in percent water 7 solution are added to the bath and the skins are left in i the bath for /2 hour during which period a water insoluble compound is precipitated on the skins. The skins are then washed and fat liquored with 4rrpounds of sulphonatedspermoil; I; 25 1 a EF V 1 00 pounds of calf skin, chrome tanned and shaved,

'are put into a drum; containing a-washing solutionand V are washed for,% hour; dlhefldrum is drained and J14 'pounds' of a mixture prepared in accordance with Ex- 80 ample XVIII is added, said mixture comprising a dicy'an i diamide-formaldehyde resin modified by diacetylene urea.

j and the sodium salt. of disulfo dinaphthyl methanel .Seyen' gallons of water are added along with theabove v 85 mixture. The skins are ethen treated with th'e'bath for .1

rhloorpoundsrbf calf rskin,rchromemamed Shaved, hour. /2 pound of sulfurrc acid 66.. Be. 1s then added. are put into a drum containingan aqueous washing some tion and are washedfoi' /4 hour; The drum is. drained "and"13' lbs. of a mixture prepared in accordance ExampIeXXI ise added, said mixturee comprising a di- 0 "The skins'arejleft in the bathfior .4. hour'duringwhich 'period a water insoluble-resinous compound is precipi: tated on the skins. The. skins arethen washed andare fat liquored with 4 pounds .sulphonated spermoiL- 1 'f a ExqmpleXXVIII r H 100 pounds of calf skins, chrome tanned and shaved,

I are-putlin'to a drum. containing awashi'ngsolution and .are washed ,for ;hour. -;Tl1. drum is drainedland 3 J a pounds of a'modifiedlamino formaldehyde resin prepared i 1 in accordancelwithExample' Xi along-with] gallons of Waterare addedtojthe drum, said resin being a dicyandiivarnide-formaldehyde resin modifiedby diacetylene urea.

added and the skins are left inthe bath for hour dur-" .15 using which period awater insoluble compound is precipi:

iThe' skins are trea ed, with theresin bath for 15 hour, after i 5 which .6 pounds of disulfo dinaphthyl methane"are added to the bath 'and the skinsare'left in the bathfor /z hour 1-. V z x, .Example, XXIV I p L fiduring ,whichperiod a'water'solublepompound pre-" 7 100 pounds of calf skins, chrome tanned and shaved; f 'f li fll s s m s n h 1 are put into a drum containing an aqueous washing solu- 5 fatllquol'ved wi h i P q l hfi i sperm 9 l if 7- Qtion and are washed'fior hour. The drum is drained a a a and llpounds of a {modified amino-formaldehyde resin V ipreparedin accordance with Example XIL along with 7 l igallonsxofwater, are added tothe drumgflsaid aminonformaldehyde.resin'being a dicyandiamide formaldehyde resinlfmodifiedby dicyandi'amidei 7 Theskins are treated with thezresin bath for lhourfafter which, 10 pounds r of solution of disulfo-dihydr'oxy diphenyl propane" C ate added'to gthe' bath and the skins are left in the bath J'fforj A bour during which period a water insoluble com- 'Ejcqmple a a.

' I09 "pounds or maskin chrometanndand 1156521, 7 j are put into a washing solution and arewash'ed for I hour. The drum is drained/and 12lbs. of amixt urelpriepared in accordance Example XIX 'is added, said" a mixture comprising a ureaefo'rmaldehyde 'resin'modified:

by n d the sodiumsalt of sdi's'ulfo 'dinaphth'yl i methane iini 35% water solution. Seven;gal1onsfof;water f' p are added along with theabove'mixture. The skins are 1 1f],- gputinto a drum containing a washing solution andrar'e I awashedtor l houn'QThe rimmisdrainedvand 1-2,-lbs.'

. is precipitatedon the The skins are then? .washed'andfat liquored with pounds of sulphonated E rca mplelXXVif '7 i:

. pounds ot sulphoi1atedspermfoil-. l;

' i1 0 of calf skin, chrome tanned andsha edQareQ 1 7 fofa' mixtnreprepared inQacc rdanCefWith nxam lexvn' poundsof calf chnometanned narrated; are f i :ilS deialong ,w1 th"lgallons of :Water, said mixture'com in {*put in'toifa 'drumkcontaining awashingsolutionandi ge a 1 P1181313 mi i f f iiii f i i ii jm P fi ;bY ':--7 :Was'hed f l qh r; ame-s r i zdra ne end ;Pbuh s V 9 of a mixture prepared in accordance with Example XX is added, said mixture comprising a melamine-formaldehyde resin modified by urea and the sodium salt of disulfo dinaphthyl methane in 35% water solution. Seven gallons ofwater are added along with the above mixture. The skins are then treated with the bath for 1 hour. /2 pound of sulfuric acid then added and the skins are left in the acid bath for A hour during which period a water insoluble compound precipitated on the skins. The skins are, washed for /2 hour and are fat liquored with 4 pounds sulphona'ted sperm oil.

Example XXXI IOU-pounds of calf skin, chrome tanned and shaved, are put into a drumcontaining a washing solution and are washed for hour. The drum is drained and 13 lbs. of a mixture prepared in accordance with Example XXII is added, said mixture comprising a dicyandiamide-formaldehyde resin modified by diacetylene urea and the sodium salt of disulfo dihydroxy diphenyl sulfonate in 50% water solution. Seven gallons of water are added along with the above mixture. The skins are then treated with the bath for 1 hour. /2 pound of sulfuric acid 66 B. is then added and the skins are left in the bath for 4 hour during which period a water insoluble compound is precipitated on the skins. The skins are then washed for /2 hour and are fat liquored with 4 pounds of sulfonated sperm oil.

Example XXXII 100 pounds of calf skin, chrome tanned and shaved, are put into a drum containing a Washing solution and are washed for 4 hour. The drum is drained and 3 pounds of a modified amino-formaldehyde resin prepared in accordance with Example XIV, along with 7 gallons of water, are added to the drum, said resin being a dicyandiamide-formaldehyde resin modified by diacetylene urea. The skins are treated with the resin bath for 1 hour, after which, 7 pounds of disulfo-dihydroxy, diphenyl sulfone are added to the bath and theskins are left in the bath for /2 hour during which period a water insoluble compound is precipitated on the skins. The skins are then washed and fat liquored with 4 pounds of sulphonated sperm oil.

Example XXXIII 100 pounds of calf skin, chrome tanned and shaved, are put into a drum containing an aqueous washing solution and are washed for A hour. The drum is drained and 9 lbs. of the sodium salt disulfo-dihydroxy diphenyl propane along with 7 gallons of water are added to the drum, and the skins are treated with this composition for hour. 4 pounds of a modified amino-formaldehyde resin prepared in accordance with Example )G] are then added to the drum bath and the skins are treated with the bath for 1 hour. /2 pound of sulfuric acid is then added to the bath and the skins are left in the acid bath for hour during which period a water insoluble compound is precipitated on the skins. The skins are then washed for V2 hour and are fat liquored with 4 pounds of sulphonated sperm oil.

Example XXXI V 100 pounds of calf skin, chrome tanned and shaved, are put into a drum containing an aqueous washing solution and are washed for hour. The drum is drained and 9 lbs. of the sodium salt disulfo-dinaphthyl methane along with 7 gallonsof water are added to the drum, and the skins are treated with this composition for A hour. 4 pounds of a modified amino-formaldehyde resin prepared in accordance with Example I are then added to the drum bath and the skins are treated with the bath for 1 hour. 95 pound of sulfuric acid is then added to hour. ,duringwhicli period a waterinsoluble compound is' precipitated on the skins, The skinsare then. washed forJ/z hour and are fat liquor-ed with 4 pounds; of sulphonated sperm oil.

The treated leather products obtained by the process disclosed in the above Examples XXIII to )QiXVDI have increased tensilestrength, increased resistance to cracking, incrasedresi'stance to abrasion and .havean increased flexibility than prior to treatment. Other materials which may be treated by this process are paper, fabrics, woodwork, etc.. wherein the water insoluble compound precipitated on the object'beingtreated acts as a filler, modifying agent, etc.

The invention in its broader aspects isnot limited to the specific steps and compositions described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

I claim:

1. A process for the preparation of a modified aminoformaldehyde resin having cationic'active properties and which is stable in water and will not heat polymerize or condense therein, comprising reacting at a temperature in the range of about 75 C. to about C. (a) a water-soluble, amino-formaldehyde resin containing free unreacted methylol groups which impart instability to said amino-formaldehyde resin in water, said amino-formaldehyde resin being selected from the group consisting of urea-formaldehyde resins, thiourea-formaldehyde resins, guanidine-formaldehyde resins, acetylene diurea-formaldehyde resins, melamine-formaldehyde resins and dicyandiamide-formaldehyde resins with (b) a water-solu ble amino base selected from the group consisting of urea, thiourea, guanidine, acetylene diurea, melamine and dicyandiamide, the water-soluble amino base being in an amount sufficient to react with all of the methylol groups of the amino-formaldehyde resin, said reaction being carried out at a pH of about at least 7.

2. A modified amino-formaldehyde resin prepared in accordance with claim 1. V

3. A process according to, claim 1 wherein the aminoform'aldehyde resin is a urea-formaldehyde resin. 7

4. A process according to claim 1 wherein the aminoformaldehyde resin is a thiourea-fo-nnaldehyde resin.

5. A process according to claim 1 wherein the aminoformaldehyde resin is a guanidine-formaldehyde resin.

6. A process according to claim 1 wherein the aminoforrnaldehyde resin is an acetylene-formaldehyde resin."

7. A process according to claim lwherein the aminoformaldehyde resin is a melamine formaldehyde resin.

8. A process according to claim 1 wherein the aminoform aldehyde resin is a dicyandiamide-formaldehyde resin.

'9. A process according to claim 1 wherein the amino base is urea.

10. A process according to claim 1 wherein the amino base is thiourea.

'11. A process according to claim 1 wherein the amino base is guanidine.

12. A process according to claim 1 wherein the amino base is acetylene diurea.

13. A process according to claim 1 wherein the amino base is melamine;

14. A process according to claim 1 wherein the amino base is di-cyandiamide.

15. A modified amino-formaldehyde resin prepared in accordance with the process of claim 3.

16. A modified amino-formaldehyde resin prepared in accordance with the process of claim 4.

17. A modified amino-formaldehyde resin accordance with the process of claim 5. V

'18. A modified amino-formaldehyde resin'prepared in accordance with the process of claim 6.

prepared in UNITED STATES PATENT OFFICE CERTIFICATE 6F CORECTION Patent No, 2 944 046 July 5 1960 Lucien Sellet It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent, should read as "corrected below.

Column 9, line 21, for 'sulfonetey read sulfone Signed and sealed this 24th day of beftober 19610 (SEA L) Attest:

ERNEST W.- SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents USCOMM-DC 

1. A PROCESS FOR THE PREPARATION OF A MODIFIED AMINOFORMALDEHYDE RESIN HAVING CATIONIC ACTIVE PROPERTIES AND WHICH IS STABLE IN WATER AND WILL NOT HEAT POLYMERIZE OR CONDENSE THEREIN, COMPRISING REACTING AT A TEMPERATURE IN THE RANGE OF ABOUT 75*C. TO ABOUT 110*C. (A) A WATER-SOLUBLE, AMINO-FORMALDEHYDE RESIN CONTAINING FREE UNREACTED METHYLOL GROUPS WHICH IMPART INSTABILITY TO SAID AMINO-FORMALDEHYDE RESIN IN WATER, SAID AMINO-FORMALDEHYDE RESIN BEING SELECTED FROM THE GROUP CONSISTING OF UREA-FORMALDEHYDE RESINS, THIOUREA-FORMALDEHYDE RESINS, GUANIDIEN-FORMALDEHYDE RESINS, ACETYLENE DIUREA-FORMALDEHYDE RESINS, MELAMINE-FORMALDEHYDE RESINS AND DICYANDIAMIDE-FORMALDEHYDE RESINS WITH (B) A WATER-SOLUBLE AMINO BASE SELECTED FROM THE GROUP CONSISTING OF UREA, THIOUREA, GUANIDIEN, ACETYLENE DIUREA, MELAMINE AND DICYANDIAMIDE, THE WATER-SOLUBLE AMINO BASE BEING IN AN AMOUNT SUFFICIENT TO REACT WITH ALL OF THE METHYLOL GROUPS OF THE AMINO-FORMALDEHYDE RESIN, SAID REACTION BEING CARRIED OUT AT A PH OF ABOUT AT LEAST
 7. 